Effect Of Abrasive Particle Size Research Articles

On the Construction Methodology of Microabrasion-Corrosion Maps Using Theoretical Approaches

In the field of microabrasion-corrosion, there has been limited research progress in modelling the process due to the complex interplay between the two processes involved. One of the crucial developments in the field has been the microabrasion-corrosion maps based on experimental results. However, mathematical modelling to develop the maps has not been attempted before. This work aimed to construct mathematical models for predicting the microabrasion-corrosion rate for mild steel and pure titanium in aqueous slurry conditions. The methodology developed was used for the construction of microabrasion-corrosion maps. The maps were constructed in two forms: (1) regime maps that identify the underlying mechanisms of microabrasion-corrosion and (2) wastage maps that identify the magnitude of the wastage rate. The effects of abrasive particle size and solution pH were shown on the maps. These maps have not been reported before and can form a basis for material selection and process optimisation for various microabrasion-corrosion applications, such as hip joint conditions. The advantages and applications of these maps are addressed in this paper.

Effect of Abrasive Grain Concession on Micromechanical Behavior of Lapping Sapphire by FAP.

Aiming at exploring the material removal mechanism for sapphire using diamond abrasive grains at the microscopic level, this paper modeled and analyzed the microscopic yield behavior of diamond abrasive grains in the FAP grinding process of sapphire. Molecular dynamics were used to simulate the effects of abrasive particle size on the cutting force, potential energy, and temperature in the Newtonian zone during micro-cutting. The effect of different abrasive particle sizes on material removal was analyzed through experiments. The simulation results show that the abrasive particle radius was 12 Å, the micro-cutting force reached more than 3500 nN, while the cutting force with an abrasive particle radius of 8 Å only reached 1000 nN. Moreover, the potential energy, cutting force, and temperature in the Newtonian zone between the sapphire crystal atoms also increased. The results showed that the material removal rate saw a nonlinear increasing trend with the increase in particle sizes, while the surface roughness showed an approximately linear increase. Both of them showed a similar trend. The experimental results lay a theoretical basis for the selection of the lapping process parameters in sapphire.

Effect of abrasive particle size on the tribological behavior of thermal sprayed WC-Cr3C2-Ni coatings

In order to improve the wear performance of ball mill liners, two types of WC-Cr3C2-12Ni coatings with different Cr3C2 contents were prepared based on high- velocity oxygen fuel (HVOF) spraying technology. The three-body abrasive wear behavior of the WC-10Cr3C2-12Ni (W10N) and WC-30Cr3C2-12Ni (W30N) protective coatings under different particle sizes was systematically evaluated. Results show that the phase composition, microstructure, and mechanical properties of WC-Cr3C2-12Ni coatings were influenced by Cr3C2 content. A large amount of WC phase with good dispersion and fine morphology must be maintained to improve the wear resistance of the coatings. The friction coefficient of both coatings was the lowest when the abrasive particle size was 12.0 µm, but it was still lower than under the no-particle condition. In addition, the friction coefficient of the W30N coatings fluctuated when the particle size were 1.5 and 4.0 µm. The primary wear mechanisms of the two coatings without particles were oxidation wear and fatigue wear, respectively, and the microstructure unevenness and low WC volume fraction led to serious wear of the W30N coatings by preferential removal of the binder phase and pull-out of the WC. The wear mechanisms of the coatings after adding small to large particles were as follows: abrasive particles protected the coatings; rounded the WC grains; and planed the coating to exfoliate in layers. By contrast, the wear resistance of the W10N coatings was obviously superior to that of the W30N coatings. Importantly, the particle size influenced the counter-balls more than the coatings. This study provides potential applications for the surface protection and life extension of ball mill liners.

Surface and subsurface microscopic characteristics in sapphire ultra-precision grinding

To investigate surface and subsurface microscopic characteristics, the ultra-precision grinding experiments of sapphire were carried out by the minimal parameter cycle method. The effects of grinding wheel grit sizes and grinding cycles number on surface and subsurface characteristics were investigated. It was confirmed that the full ductile damage-free surface with Sa10nm can be achieved, and the microscopic characteristics of rough grinding and ultra-precision grinding surfaces are different. The effect of abrasive particle size on surface roughness and grinding wheel profile wear was discussed. Moreover, the subsurface characteristics were surveyed through molten KOH corrosion, the subsurface marks and subsurface damage were observed. The subsurface damage was dominated by median cracks, it can be observed under the ductile surfaces.

The Use of Surfacing Materials to Increase the Durability of Disc Harrow Working Elements

Introduction. For surface tillage operation there widely used disc harrows, working bodies of which are discs wearing out during operation. The wear intensity of discs depends on the wear resistance of their working surfaces, working modes and properties of the cultivated soil. It has been found that an effective way to increase the life of discs is surfacing them with wear-resistant materials. The aim of the work is to study the wear out of surfacing materials, which can be used to harden discs and to make recommendation for the use of these materials in the repair departments of agricultural enterprises. Materials and Methods. Surfacing with electrodes T-590 and powder wires PP-Np200Kh15S1GRT, VELTEK-N560.02 and PP-Np280Kh9F7SG4 were taken as test materials. For wear tests of materials in abrasive mass, there was used an apparatus to simulate the moisture content and composition (sandy loam or loam) of the soil. In the disk-pad tests, the effect of abrasive particle size, load and sliding friction velocity on the wear of the materials was studied. In field tests, wear of the disks made of 65G steel, surfaced toothed and solid disks were monitored. Results. Laboratory studies of the materials revealed the effect of soil moisture and composition, load, abrasive grit and sliding friction velocity on wear. The main factor determining the wear resistance of materials is their structural state. The indexes of wear resistance of surfacing were determined during the laboratory tests and confirmed by field tests. Discussion and Conclusion. Surfacing with flux-cored wire PP-Np280Kh9F7SG4 has the highest wear resistance of the studied materials. The technology of hard-facing disks with modern materials, in particular with flux-cored wire PP-Np280Kh9F7SG4, can be implemented in repair departments of agricultural enterprises when they have the equipment for hard-facing and sharpening of working surfaces.

Experimental characterization of conformal hydrodynamic nanopolishing of a machined single crystal sapphire cavity

Sapphire is an important ceramic material which finds applications in fields such as temperature sensing, optics, electronics, and ceramic bearings. Polishing of sapphire has always been a difficult task for industries and research communities. Hydrodynamic polishing (HDP) is one of the prominent methods used for polishing of hard and profiled surfaces, whereas rigid tool-based methods such as diamond turning, grinding, and honing have many limitations. The HDP process involves deterministic flow of abrasive particles in the slurry between the workpiece surface and a rotating soft tool to obtain the desired surface finish. A novel experimental setup has been fabricated to realize the conformal hydrodynamic nanopolishing on single crystal sapphire cavity. In this study, the experiments were conducted to understand the effect of abrasive particle size, basicity of slurry, and change in temperature of slurry on the polishing of machined sapphire cavity. The effect of the initial surface roughness of the machined cavity on conformal hydrodynamic nanopolishing has also been investigated. A microcrack/pit-free surface has been found after the final polishing of the sapphire cavity. An improvement of 21% is found in surface finish after the final polishing using abrasive particle size of 0.06 µm. Abrasive slurry with higher basicity (pH 13) does not improve the surface finish. By heating the abrasive slurry to a temperature of 70°C–75°C, surface finish improves by ∼26% as compared to improvement of ∼ 21% at room temperature polishing.

Precision polishing of the mandrel for X-ray grazing incidence mirrors

Based on chemical-mechanical polishing, a precision polishing method is proposed to accommodate the polishing of the paraboloid surface of the specified mandrel for grazing incidence X-ray mirrors. The influencing factors in the polishing are analyzed to confirm the method complies with the Preston equation and Hertz contact theory. Therefore, the common material removal model based on these two theories is adopted. The effects of processing parameters, such as the force F between the mandrel and the polishing lap, the rotational speed n of the mandrel, and the axial speed va of the polishing lap, on the material removal rate are simulated, respectively. A polishing setup is established to carry out experimental polishing to verify the optimum processing parameters obtained by simulations and previous polishing tests. Besides, the effect of abrasive particle size on the roughness is also verified. The roughness of the polished mandrel is measured at different positions, and the optimum roughness reaches Ra 0.659 nm. The polishing approach can significantly reduce the surface roughness of the replication mandrel, satisfying the low energy band focusing requirement of grazing incidence X-ray mirrors.

Study on the correlation between grain size and processing limit in abrasive flow machining

The influence of particle size on the abrasive flow machining mechanism and processing limit was studied by establishing the processing model of different particle size. When many scholars studied the mechanism of abrasive flow machining in the past, they only established a machining model and ignored the effect of abrasive particle size. By comparing the size of different granularity abrasive particles and the workpiece surface in contact with each other, the large granularity abrasive particle processing model and the small granularity abrasive particle processing model were put forward, and their processing mechanism was analyzed respectively. On this basis, the reason of machining limit in different particle size abrasive processing process is explained. Finally, the theoretical analysis and experimental results were compared to verify the correctness of the processing mechanism and theoretical analysis of processing limit of abrasive with different granularity, and an optimal experimental scheme was proposed to break through the original processing limit.

Effect of abrasive particle size on tribological behavior of elastomers

Effect of abrasive particle size on tribological behaviour of different elastomers was investigated experimentally in this study. The size of abrasive particle size was varied from coarse (425 µm) to fine (82 µm). Wear rate and coefficient of friction were calculated and analyzed accordingly followed by the examination of worn surfaces by a scanning electron microscope to unravel the wear mechanism. Experimental results showed that abrasive size had a significant effect on wear and friction behaviour of the elastomers. As the abrasive particle size increased, wear rate and coefficient of friction also increased at different rates and exhibited different wear mechanisms that changed from friction to fatigue and roll formation. Mechanical properties of elastomers such as hardness, tensile strength, tear strength, and elongation at break also contributed to wear and friction. The effect of elongation at break and tensile strength on wear rate is more pronounced at lower abrasive particle size, whereas hardness and tear strength play a pivotal role at the higher abrasive size.

Semi-empirical Material Removal Model with Modified Real Contact Area for CMP

Chemical mechanical polishing (CMP) is essential in semiconductor processing and has recently widened its scope of application. However, the study on its mechanisms is still in progress. Understanding the CMP process requires an understanding of the various physical and chemical reactions that occur at the pad-wafer interface. Moreover, understanding the real contact area (RCA) between the polishing pad and the wafer in the CMP process is essential for predicting the material removal rate (MRR) and understanding the overall process. In this study, a modified mathematical model for the RCA was developed and validated experimentally. The model of the RCA proposed in this study was used to establish the MRR model and predict the MRR under various pressure values and the effect of abrasive particle size and its distribution. Specifically, the experimentally obtained values were compared with the values obtained by the model and the comparison results were analyzed. Thereby, it was found that the RCA model and the MRR model proposed in this study were in good agreement with the experimental results, which shows that the MRR can be predicted by a mathematical model using the measurement of the RCA.

Experimental and simulation studies of abrasive particles impacting monocrystalline silicon in suspension thin film flow field of ultrasonic polishing

In ultrasonic polishing (USP), when the gap between the polishing tool and workpiece is small enough, the suspension seeped into it can be considered as suspension thin film (STF). STF flow field provides a periodic oscillation condition for abrasive particles, which can improve abrasive particle cutting performance by changing its behavior. It is very effective for improving the polishing efficiency and surface quality of hard-to-machine materials. However, the interaction behavior of target material, STF flow field, and abrasive particle in USP has rarely been studied. In this paper, to fulfill a fundamental understanding of this field, the behavior of abrasive particles impacting monocrystalline silicon in STF flow field is investigated by experimental and simulation methods. At macro-level, through the study of ultrasonic amplitude, abrasive particle size, and polishing tool rotational speed in USP experiments, the positive role of STF flow field has been revealed, and the change characteristic of surface roughness is obtained. The computational fluid dynamics (CFD) simulation results show that strong transverse shear flow is formed in STF, which plays a major role in material removal. At micro-level, novel mathematical models of plastic deformation and brittleness removal and material removal mechanism of STF flow field are proposed. Comprehensive analysis of blunt and sharp abrasive particles impacting monocrystalline silicon is implemented through finite element method (FEM), which includes the effect of abrasive particle size on material removal rate (MRR), kinetic energy change of abrasive particle, force analysis of impact, the effect of impact angle, and polishing tool rotation on MRR. The final results show FEM simulation results are consistent with that of CFD simulation and experiments, which is of great significance to reveal the behavior principle of abrasive particles in STF and guide the actual production.

Effect of abrasive particle size on friction and wear behaviour of HVOF sprayed WC-10Co-4Cr coating

The objective of the present work is to investigate the effect of abrasive particle size on friction and abrasive wear performance of HVOF sprayed WC-10Co-4Cr coating. WC-10Co-4Cr coating was deposited by HVOF technique on 316 SS substrate. Friction coefficient and abrasive wear rates were measured with varying abrasive particle size, load and sliding speed. The microscopic observations, XRD and XPS analyses of worn surface were used to analyze friction and wear data. The increase in abrasive wear rate with an increase in load and abrasive particle size was attributed to the transition in wear mechanisms. The variation in friction coefficient with abrasive particle size as a function of load and sliding speed was due to change in the contribution of adhesion and abrasion, and varying degree of tribo oxidation. With increasing sliding speed abrasive wear rate and friction coefficient decreased, which was due to the dominance of oxidative wear. The prevalence of fracture dominated mechanical wear processes led to an increased coefficient of friction at higher load.

Effect of Abrasive Particle Size on Lapping of Sapphire Wafer by Fixed Abrasive Pad

The choice of abrasive particle size is crucial to improve the lapping efficiency and surface quality in lapping of sapphire wafer by fixed abrasive (FA) pad. A model for the penetration depth of a single abrasive is developed with fixed abrasive pad. A serious of lapping tests were carried out using FA pads embedded with different size of diamond particles to verify the validity of the developed model. Results show that the penetration depth of abrasive is related not only to the particle size, but to the hardness ratio of the work-piece to the pad as well. The material removal rate of sapphire is proportional to the square of abrasive particle size, while the average surface roughness is proportional to the abrasive particle size.

Effect of abrasive particle size on friction and wear behaviour of various microstructures of 25CD4 steel

Many parameters, such as normal load and material bulk hardness, control the wear and friction behaviours of materials. Nonetheless, the investigation of the coupled contributions of microstructure and abrasive particle size are still lacking. A contribution is proposed by using steel pins with various microstructures with a similar macro-hardness (around 410HV) and chemical composition. A quenched martensitic microstructure, a tempered martensitic microstructure and three ferrite-martensite dual-phase microstructures, with a similar martensite volume fraction (around 67%) and different martensite colony morphologies, are established. Friction tests are performed between these pins and abrasive papers with different sizes ranging from 15μm to 200μm. Compared to single-phase microstructures (quenched and tempered martensitic microstructures) and whatever the abrasive particle size, ferrite-martensite dual-phase microstructures reduce the friction coefficient and provide better wear resistance. For the ferrite-martensite dual-phase microstructures and unlike fine and fibrous martensite colonies, coarse and granular martensite colonies minimize the friction coefficient. In addition, characterized by a change of wear mechanisms between abrasion and adhesion, an intermediate abrasive particle around 35 μm minimizes the friction coefficient. This study also reveals that the wear rate increases with the abrasive particle size which is associated to an increase of the attack angle of abrasive grains.

Effect of abrasive particle size on slurry abrasion resistance of austenitic and martensitic steels

The effects of the abrasive particle size and the pH-value of the aqueous solution on the abrasive wear resistance of H–13 steel and Hadfield steel were investigated. Abrasive wear tests, using a wet rubber wheel abrasion tester, were carried out applying abrasive sizes in the range of 0.15–2.40mm. The pH-values of the aqueous solution ranged from 5.5 to 12.8. The microstructure of each material was characterized with optical microscopy. The wear surfaces and the wear particles (debris) were analyzed by scanning electron microscopy (SEM). The macro- and microhardness were measured before and after the wear tests using a Vickers hardness tester. The surface topography of the wear scars was examined by a non-contact 3D profiler in order to measure the depth of the abrasive penetrations.The results demonstrated that Hadfield steel is more wear resistant than H-13 steel for all pH-values and all abrasive particle sizes used in the tests. Moreover, the micro-hardness of the wear scar surface of the Hadfield steel increased significantly with the size of the abrasive grain, while this increase was lower for the H-13 steel. The greater work-hardening of the austenitic Hadfield steels was considered to be responsible for this higher wear resistance in comparison with the martensitic H-13 steel. For both materials the loss of mass increased linearly up to a critical abrasive particle size (CPS); this CPS, the mass loss continued to increase but with a lower gradient. An explicit effect of the steel matrix on the mass loss behavior as a function of the abrasive grain size was not observed. The less acidic aqueous solution resulted in lower mass losses for both materials and for all abrasive grain sizes. This effect was greater for the two smaller abrasive grain sizes. For higher pH-values, lower depths of penetration of the abrasive particles were observed. The analysis of the wear particles in all test conditions displayed continuous and discontinuous chips for the H-13 steel but only discontinuous chips for the Hadfield steel,. For both materials two abrasive wear micromechanisms were determined: microcutting and microploughing. Finally, the results presented in this work suggest that the wear performance analysis of Hadfield steel, to be used in an abrasive environment, should consider the effects of the pH value of the aqueous solution and the abrasive particle size.

Effect of abrasive particle size on tribochemical wear of monocrystalline silicon

Using atomic force microscopy, the nanowear of hydrogen-terminated silicon surface was investigated in water with spherical SiO2 tips. The radii of tips can significantly affect the material removal of silicon surface and large tip could result in substantial wear and high friction force. Analysis suggests that the increase in contact area could enhance the tribochemical reaction by forming more Si-O-Si bonding bridges at Si/SiO2 interface. Thus, for the tribochemical wear of silicon under elastic contact condition, the abrasive particle size dependence of material removal was more attributable to the change of contact area than to the change of indentation volume. These results may help gain a profound insight into the influence of abrasive particle size on tribochemical wear of silicon.

I-11 サファイアCMPにおけるコロイダルシリカと水酸化フラーレンの混合スラリーの最適化

This research studies the method to optimization of polishing slurry which colloidal silica based (SiO_2 slurry) containing C_<60>(OH)_n n=ca.10 for Chemical Mechanical Polishing (CMP) process by concentration dependence on the C_<60>(OH)_n solute between 0-0.05 wt% and varying size of abrasive particle in colloidal silica slurry between 20-55 nm. We focussed on relationship between the effect of abrasive particle size and polishing performance such as Material Removl Rate (MRR) and surface roughness of sapphire substartes. This paper consists of two parts, the first section in order of slurry preparation and polishing condition setting up for CMP process. The last section are the MRR value calculating and abrasive particle diameter size before and after CMP process measuring for optimization of mixed colloidal silica and fullerenol slurry in CMP of sapphire. These results indicate that diameter of the fine particle composed by colloidal silica slurry and C_<60>(OH)_n is a dominant parametrs to determid the MRR values against the apphire CMP.

Abrasive Size Effect on Friction Coefficient of AISI 1045 Steel and 6061-T6 Aluminium Alloy in Two-Body Abrasive Wear

In this study, the effect of abrasive particle size on the friction coefficient and specific cutting energy of AISI 1045 steel and 6061-T6 aluminium alloy in two-body abrasive wear was investigated. Abrasive wear tests using a pin on alumina paper were carried out using abrasive sizes between 16 and 192 μm. The wear surface of the specimens was examined using SEM to identify the wear micromechanism and the type of microchips (wear debris) formed on the abrasive paper in order to correlate with the friction coefficient and the specific cutting energy values. Results show that the 6061-T6 aluminium alloy presents a higher friction coefficient than the SAE 1045 steel for every abrasive size tested. The friction coefficient increases linearly to 36 μm and after that increases at a reduced linear rate and becomes constant above 116 μm for both materials tested. The results show that there are two main energy-consuming mechanisms in friction measurements: plastic deformation and microchip formation. The specific cutting energy decreases with the increase in abrasive size and after 116 μm become constant for the materials tested.

Friction and Wear Mechanisms of 316L Stainless Steel in Dry Sliding Contact: Effect of Abrasive Particle Size

The present work investigates the dry sliding friction and wear behavior of 316L austenitic stainless steel. Wear tests are performed on a pin-on-plane configuration against abrasive silicon carbide grains ranging from very large (200 μm) to small (15 μm) particles. The experiments are conducted at room temperature under different normal loads of 25–75 N. The wear damage mechanisms and wear debris are analysed using scanning electron microscope (SEM) observations. It is shown that for small abrasive particles, the friction coefficients increase with increasing normal load. However, for large abrasive particles, a reverse trend is observed. This difference is partly explained by a change in wear mechanisms.Finally, surface roughness measurment of the worn surfaces are performed after wear tests. The relationship between the 3D fractal dimension and wear rate is investigated based on fractal theory. The 3D fractal analysis of the worn surfaces showed that higher values of fractal dimensions indicate a larger real contact area and therefore a better wear resistance of the 316L stainless steel.

A Modified Surface on Titanium Alloy by Micro-Blasting Process

Hydroxyapatite (HA) coating of hard tissue implants is widely employed for its biocompatible and osteoconductive properties as well as its improved mechanical properties. In this study, a novel micro-blasting process has been used to successfully modify a titanium alloy substrate with a HA treatment using a dopant/abrasive regime. The impact of a series of apatite abrasives, was investigated to determine the effect of abrasive particle size on the surface properties of both micro-blasting (abrasive only) and continuous (HA/abrasive) treatments. The resultant HA treated substrates were compared to substrates treated with abrasive only (micro-blasted) and an untreated Ti. The HA powder, apatite abrasives and the treated substrates were characterized for chemical composition, coating coverage, crystalline and topography. The results show that the surface roughness of the HA blasted modification was affected by the particle size of the apatite abrasives used. This study demonstrates the ability of the continuous process to deposit HA coatings with a range of surface properties onto Ti alloy substrates. The ability of the continuous technology to offer diversity in modifying surface topography offers exciting new prospects in tailoring the properties of medical devices for applications ranging from dental to orthopedic settings.